Holy crap! My FPS are freaking awesome.
I was so disappointed when my second 5870 started to wink out. I needed both in Crossfire to get decent FPS level with the HD pack, on Ultra at 1920x1200, 8AA, 16AF, shadow detail= medium.
After reading this thread I decided to go see how my game would run. (I got 1.4, and new GPU drivers since my last play session.) To my amazement, I get 60 FPS 99.9% of the time......on 1 card.

If I turn quickly, it can still dip into the 30's but it bounces back to 60 pretty quickly.
The "Whiterun stair FPS drop" issue non-existent now!

(60 to 30 FPS on the stairs to the castle when turning back to look at the business section of town.)
Sweet! I can go back to playing.